The present disclosure relates to the subject matter contained in Japanese Utility Model Application No. 2002-001108 filed Mar. 6, 2002, which is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a mounting structure of a flyback transformer equipped in a power circuit for a video apparatus such as a television receiver.
2. Description of the Related Art
FIG. 4 is an exploded perspective view showing the conventional structure of a flyback transformer mounting portion in a television receiver equipped with a flyback transformer (FBT) of this kind. In FIG. 4, 1 denotes a chassis, 2 denotes a main wiring board fixed to the chassis 1 by screws, 3 denotes a power circuit wiring board formed with a power circuit, 4 denotes the flyback transformer mounted on the power circuit wiring board 3, 5 denotes a holder to which the power circuit wiring board 3 is fixed by screws. The chassis 1 with the main wiring board 2 attached and the holder 5 for holding the power circuit wiring board 3 with the flyback transformer 4 mounted are accommodated in a cabinet. The heavy flyback transformer mounted on the power circuit wiring board 3 is supported by the holder 5 that is fixed to the cabinet by screws. In FIG. 4, 6 denotes a screw used for fixing the power circuit wiring board 3 to the holder 5.
In JP-A-5-343236 (prior example 1), there is disclosed a mounting structure in which a plate-like shield reinforcing fitting is coupled to a printed wiring board and raised from the printed wiring board, and a flyback transformer is fixed to the shield fitting by screws. Also, there is disclosed a mounting structure in which a boss at the top of the flyback transformer mounted on the printed wiring board is fixed by a screw via a holding device to a back cover, thereby preventing the flyback transformer from being moved back and forth, or right and left, when an impact load is applied. Also, in JP-A-6-124837 (prior example 2), there is disclosed a mounting structure in which a printed board with a flyback transformer mounted is fixed by screws to a receptacle as the holder, which is attached on a bottom plate of the cabinet, a boss at the top of the flyback transformer is loosely inserted into a through hole formed in an end plate of the cabinet, and a collar head screw is fitted into the boss to restrict a clearance width.
However, in the conventional flyback transformer mounting structure as shown in FIG. 4, since the holder 5 is provided separately from the chassis 1 and fixed to the cabinet by screws, the holder is required in excess and an operation process for attaching the holder to the cabinet is also needed in excess, which imposed restrictions on reducing the price.
On the contrary, in the mounting structure in which the flyback transformer is fixed by screws to the shield reinforcing fitting of prior example 1, the heavy flyback transformer is supported only by the soldered portion with the printed wiring board, and the shield reinforcing fitting soldered to the printed wiring board. Thus, it cannot be the that the mounting structure can fully withstand an impact when dropped. Also, in the mounting structure in which the boss at the top of the flyback transformer mounted on the printed wiring board of prior example 1 is fixed by screws via the holding device to the back cover, the flyback transformer is mounted on two members of the printed wiring board and the back cover. Thus, in case where the printed wiring board and the back cover are displaced by an impact when dropped, there is a risk that a large stress is applied on a portion of attaching the boss of the flyback transformer to the back cover, thereby breaking that portion.
In the prior example 2, the flyback transformer is just restricted moving more than a predetermined amount by an impact when dropped. Thus, it is difficult to say that the mounting structure is able to fully support the heavy flyback transformer against the impact when dropped. Also, the holder is required in excess, and the operation process for attaching the holder to the cabinet is required in excess, resulting in a problem that they impose restrictions on reducing the price.
This invention has been achieved in the light of the above-mentioned problems, and it is an object of the invention to provide a flyback transformer mounting structure for a video apparatus which can securely support a heavy flyback transformer with a high impact resistance against an impact when dropped, in which the flyback transformer is mounted on a main wiring board formed with a power circuit for connecting with the flyback transformer, and a holder for holding a power circuit wiring board is omitted to reduce the price.
The present invention provides a flyback transformer mounting structure for a video apparatus, comprising: a main wiring board; a power circuit formed on the main wiring board; a flyback transformer mounted on the main wiring board, the flyback transformer having a mounting portion; a chassis to which the main wiring board is attached; and a mounting bracket linked integrally with the chassis, wherein the mounting portion of the flyback transformer is fixed by a screw to the mounting bracket.
In this mounting structure, the main wiring board has the power circuit, whereby the flyback transformer mounted on the main wiring board can be connected to the power circuit. Therefore, the power circuit wiring board and the holder for holding it are unnecessary, the number of parts is reduced, and the operation process for fixing the power circuit wiring board to the holder and the operation process for fixing the holder to the cabinet are unnecessary, whereby the price is reduced. Also, the mounting portion of the flyback transformer is fixed by a screw to the mounting bracket linked integrally with the chassis, and the mounting bracket is preferably fixed by a screw to the cabinet, whereby the chassis and the mounting bracket are unmovably supported by the cabinet, and the heavy flyback transformer is held by the chassis and the mounting bracket linked integrally with the chassis. Hence, even if the chassis with the mounting bracket and the cabinet are displaced due to an impact when dropped, its influence is not applied on the mounting portion (including the connecting portion by solder) of the flyback transformer to the chassis and the cabinet, so that the excellent impact resistance is exhibited.
In this invention, it is preferable that the chassis and the mounting bracket are integrally molded of synthetic resin, and the mounting bracket is shaped like an L-character in plan view, and raised at the corner portion of the chassis. In this case, the chassis and the mounting bracket are integrally molded of synthetic resin, so that the mounting bracket is not shaken with respect to the chassis. Also, the mounting bracket is shaped like an L-character in plan view, and raised at the corner portion of the chassis, so that the strength of the mounting bracket is increased by the shape of L-character in plan view, thereby serving to support the heavy flyback transformer securely and steadily.
Also, this invention provides a flyback transformer mounting structure for a video apparatus, comprising: a main wiring board; a power circuit formed on the main wiring board; a flyback transformer mounted on the main wiring board, the flyback transformer having a mounting portion provided on an upper end thereof and an adjusting screw; a chassis to which the main wiring board is attached; and a mounting bracket shaped like an L-character in plan view, molded of synthetic resin integrally with the chassis and raised at a corner portion of the chassis, the mounting bracket having an opening and a pair of longitudinal ribs interposing the opening therebetween, wherein the mounting portion of the flyback transformer is fixed by a screw to an upper end portion of the mounting bracket, a middle portion of the mounting bracket in a height direction is fixed by a screw to a cabinet of the video apparatus, and the adjusting screw of the flyback transformer faces the opening of the mounting bracket.